Field of the Invention
The present invention relates to a communication system and technologies relating thereto.
Description of the Related Art
There are technologies (intra-body communication technologies) for communication using an electrostatic field at the surface of a user's body (refer to JP 2013-46337 A).
With such an intra-body communication technology, data communication is carried out by using the charge stored in the human body, and is thus susceptible to noise. For example, JP 2013-46337 A discloses a technology to improve the SNR (signal-to-noise ratio) to stabilize communication by increasing an area of contact with a human body when the SNR has become lower than a threshold.
It may be, however, difficult to increase the contact area as disclosed in JP 2013-46337 A depending on the situation.
Alternatively, the communication strength (signal strength level) may be increased by using other methods to stabilize communication. If communication strength is always controlled to be increased, however, there is a problem of increased power consumption. In particular, a communication unit at a human body is driven by a battery, and the period for which the communication unit can be driven by the battery (and also the period during which communication can be carried out) is shorter as the power consumption is larger.